Alcohol remains a substantial problem among American youth, and the problem of adolescent alcohol abuse varies across ethnic groups. While past studies show that friends' behaviors, along with other risk and protective factors, likely contribute to adolescent alcohol use disparities, there remains a substantial research gap on: how personal friendship networks and school social networks are related to ethnic differences in alcohol use and alcohol-related problems; what factors contribute to differences in adolescent alcohol use between specific ethnic subgroups; how same-ethnicity and cross-ethnicity friendships contribute to alcohol use disparities among adolescents and young adults; and, whether certain protective factors reduce the impact of alcohol use exposure in adolescents' personal friendship networks and school social networks. [unreadable] [unreadable] The proposed research will address these issues by analyzing data from the National Longitudinal Study of Adolescent Health (Add Health), an exceptional data set that provides comprehensive information on the adolescent experience and the transition to young adulthood. The proposed research will examine how ethnic differences in personal friendship networks, school social networks, the characteristics of best friend, and other alcohol related risk and protective factors, explain alcohol disparities during adolescence and in the transition to young adulthood. These analyses will include detailed investigations of how the structural characteristics of, and average drinking in, personal and school networks influence alcohol use and alcohol-related problems in adolescence and young adulthood. Ethnic variation in alcohol use will be compared across seven ethnic groups: African Americans, Chinese Americans, Filipino Americans, Mexican Americans, Puerto Ricans, Cuban Americans, and, non-Hispanic whites. In addition, the proposed study will address how same-ethnicity and cross-ethnicity friendships contribute to alcohol use disparities. Further, the study will investigate the relationships between protective factors (parenting, school and religious attachments, school environment) and alcohol use exposures in personal and school networks, testing for their combined effects on adolescents' and young adults' alcohol use and alcohol-related problems. Overall, the proposed study will address how adolescent experiences influence alcohol use disparities during adolescence and in the transition to young adulthood. [unreadable] [unreadable]